Electromechanical brake actuator and cam disc

Patent metadata

Field	Value
Publication number	US-12227154-B2
Application number	US-202017630983-A
Country	US
Kind code	B2
Filing date	Aug 6, 2020
Priority date	Aug 16, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

An electromechanical brake actuator ( 102, 202, 302, 402 ) for a brake has a cam disc ( 108, 108′, 108″, 208, 308, 408 ) and a brake plunger ( 114, 214, 314 ) for actuating a brake lever ( 358 ). The cam disc ( 108, 108′, 108″, 208, 308, 408 ) and the brake plunger ( 114, 214, 314 ) have contact surfaces in contact with one another for directly transmitting a drive torque. The contact surface of the cam disc ( 108, 108′, 108″, 208, 308, 408 ) extends at a distance r about the pivot point D, which is defined as a function r(φ) with a change rate r′(φ) and depends on the angular position φ of the cam disc ( 108, 108′, 108″, 208, 308, 408 ). The contact surface is configured to effect non-linear transmission between the drive torque of the cam disc ( 108, 108′, 108″, 208, 308, 408 ) and the force transmitted to the brake plunger ( 114, 214, 314 ).

First claim

What is claimed is:

1. An electromechanical brake actuator ( 102 , 202 , 302 , 402 ) for a brake, in particular a commercial vehicle disc brake, having:
an electric motor ( 106 , 206 ) for generating a driving torque,
a cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) which is rotatably mounted and operatively connected to the electric motor ( 106 , 206 ), and
a brake plunger ( 114 , 214 , 314 ) configured to move along a plunger axis, for actuating a brake lever ( 358 ) of the brake ( 368 ),
wherein the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) and the brake plunger ( 114 , 214 , 314 ) have contact surfaces which bear against each other and slide or roll on each other for directly transmitting the driving torque from the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) to the brake plunger ( 114 , 214 , 314 ),
wherein the contact surface of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) extends about a pivot point D at a radial distance r defined as a function r(φ) with a rate of change r′(φ) and dependent on an angular position φ of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ), and
wherein the contact surface is configured in such a way that there is a non-linear transfer between the driving torque of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) and the force transmitted to the brake plunger ( 114 , 214 , 314 ), wherein the radial distance r(φ) is at its minimum for an angular position where φ=φ min and is at its maximum for an angular position where φ=φ max· ,
wherein the rate of change r′(φ) is positive at least in certain regions in a first angular range φ min ≤φ≤φ max , and in that the rate of change r′(φ) is negative at least in certain regions in a second angular range φ max ≤φ≤360°,
wherein, in the first angular range φ min ≤φ≤φ max , the function r(φ) has a first function profile r 1 (φ), and, in the second angular range φ max ≤φ≤360°, has a second function profile r 2 (φ) which differs from r 1 (φ).

2. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the rate of change is r′(φ min )=0 at an angular position where φ=φ min .

3. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 2 , wherein the function r(φ) has a positive curvature at an angular position where φ=φ min such that r″(φ min )>0.

4. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the rate of change is r′(φ max )=0 at an angular position where φ=φ max .

5. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the function r(φ) has a negative curvature at an angular position where φ=φ max such that r″(φ max )<0.

6. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed claim 1 , wherein the radial distance r(φ), at at least one angular position φ=φ p ′ with φ max ≤φ p ′≤360°, changes suddenly by a value

Δ
⁢
r

≤

1
10

⁢

r
⁡
(

φ

m
⁢
ax

)

.

7. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the radial distance r(φ) increases strictly monotonically in an angular range φ min ≤φ≤φ max such that r′(φ min ≤φ≤φ max )>0.

8. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the radial distance r(φ) decreases strictly monotonically in an angular range φ max ≤φ≤360° such that r′(φ max ≤φ≤360°)<0.

9. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein r 1 (φ) and r 2 (φ) meet at at least one angular position φ 1,2 at which r 1 ′(φ) and r 2 ′(φ) are smooth.

10. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 9 , wherein the angular position φ 1,2 is a first angular position at which r 1 (φ) has a negative curvature, and wherein r 1 (φ) and r 2 (φ) further meet at a second angular position φ 2,1 at which r 2 ′=r 1 ′ and r 1 (φ) has a positive curvature.

11. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein r 1 (φ) and r 2 (φ) meet at at least one angular position φ 1,2 at which r 1 ′=r 2 ′.

12. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 11 , wherein the angular position φ 1,2 is a first angular position at which r 1 (φ) has a negative curvature, and wherein r 1 (φ) and r 2 (φ) further meet at a second angular position φ 2,1 at which r 2 ′=r 1 ′ and r 1 (φ) has a positive curvature.

13. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the function r(φ) has a transition function r 3 (φ) which meets the first function profile r 1 (φ) at a first angular position φ 1,3 , wherein r 1 ′(φ 1,3 )=r 3 ′(φ 1,3 ), and which meets the second function profile r 2 (φ) at an angular position φ 3,2 , wherein r 2 ′(φ 3,2 )=r 3 ′(φ 3,2 ).

14. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 13 , wherein the transition function r 3 (φ) is a first transition function, and the function r(φ) also has a second transition function r 3 (φ), which meets the first function profile r 1 (φ) at a third angular position φ 3,1 , wherein r 1 ′(φ 3,1 )=r 3 ′ (φ 1,3 )′, and which meets the second function profile r 2 (φ) at an angular position φ 2,3 , wherein r 2 ′(φ 2,3 )=r 3 ′(φ 2,3 ).

15. The brake actuator ( 102 , 202 , 302 , 402 ) as claimed in claim 1 , wherein the rate of change is r′(φ max ≤φ<φ p )=0 in an angular range φ max ≤φ<φ p , wherein φ max −φ p ≤0.1·(φ max −φ min )°.

16. A cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) for a brake actuator ( 102 , 202 , 302 , 402 ), the cam disc being configured to be connected to a driveshaft of an electric motor ( 106 , 206 ),
wherein the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) has a contact surface configured to bear against a contact surface of a brake plunger ( 114 , 214 , 314 ) for directly transmitting a driving torque between the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) and the brake plunger ( 114 , 214 , 314 ) in such a way that the contact surfaces slide or roll on each other,
wherein the contact surface of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) extends about a pivot point D at a radial distance r defined as a function r(φ) with a rate of change r′(φ) dependent on the angular position φ of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ), and the contact surface is configured to effect a non-linear transfer between the driving torque of the cam disc ( 108 , 108 ′, 108 ″, 208 , 308 , 408 ) and the force transmitted to the brake plunger ( 114 , 214 , 314 ),
wherein the radial distance r(φ) is at a minimum at an angular position where φ=φ min and is at a maximum at an angular position where φ=φ max ,
wherein the rate of change r′(φ) is positive at least in certain regions in a first angular range φ min ≤φ≤φ max and the rate of change r′(φ) is negative at least in certain regions in a second angular range φ max ≤φ≤360°,
wherein, in the first angular range φ min ≤φ≤φ ma

Assignees

• Zf Cv Systems Europe Bv

Inventors

• Beier Peter
• Reiners Arne
• Reiners Jan
• Moritz Christoph

Classifications

• F16D2125/50

  with parallel non-stationary axes, e.g. planetary gearing · CPC title

• F16D2125/48

  with parallel stationary axes, e.g. spur gears · CPC title

• F16D2125/32

  acting on one cam follower · CPC title

• F16D2121/24

  using motors · CPC title

• F16D65/183

  with force-transmitting members arranged side by side acting on a spot type force-applying member · CPC title